1. Technical Field
The present invention relates to image forming apparatuses such as facsimile machines, scanners, printers, copiers, and multi-functional apparatuses including at least two of such functions.
2. Description of the Background Art
Image forming apparatuses may have a power-save mode to reduce power consumption during standby by shutting down power to certain units disposed in the apparatuses.
Some image forming apparatuses have the ability to inform a user of a difference in power consumption between a normal operation mode and the power-save mode. Further, some image forming apparatuses have the ability to measure the power consumption for each operation mode and inform the user of the measured power consumption. Further, some image forming apparatuses have the ability to reduce the amount of power used when measuring power consumption of the image forming apparatus.
For example, JP-2010-000652-A discloses an image forming apparatus having a power measurement unit disposed on a power-supply line from an external power source to functional modules, such as an image forming module and a fusing module. The power measurement unit includes a current detector to detect the current supplied to each module, and a voltage detector to detect the voltage supplied to each module. In the normal operation mode, based on the current and voltage detected by the current detector and the voltage detector, the power consumption at each of the units can be computed. Further, in the power-save mode, the power supply to the voltage detector is shut down, and a projected power consumption at each of the units is computed based on information stored in advance.
However, in conventional image forming apparatus, even in the power-save mode, because the power is being supplied from the power source to the power measurement unit, a given amount of power is still consumed at the power measurement unit wastefully. As a result, power consumption may not be reduced effectively.